The signature-filing deadline for candidates wishing to run in these elections was November 2, 2009, and the primary election day was February 2, 2010.

Under the Illinois Constitution of 1970, senators are divided into three groups, each group having a two-year term at a different part of the decade between censuses, with the rest of the decade being taken up by two four-year terms. In Illinois, senators have no term limits.

The incumbent senator is running in 20 of the 21 state senate races. (95.24%)

Campaign contributions

This chart shows how many candidates ran for state senate in Illinois in past years and the cumulative amount of campaign contritubions in state senate races, including contributions in both primary and general election contests. All figures come from Follow The Money.[1]

Year

Number of candidates

Total contributions

2008

74

$25,856,554

2006

77

$27,398,829

2004

37

$17,305,449

2002

120

$34,677,544

Qualifications

Article IV of the Illinois Constitution states: To be eligible to serve as a member of the General Assembly, a person must be a United States citizen, at least 21 years old, and for the two years preceding his election or appointment a resident of the district which he is to represent.